[Bug 40720] Splinter Cell: Blacklist changing sound level has no effect

https://bugs.winehq.org/show_bug.cgi?id=40720

--- Comment #1 from Andrew Eikum  ---
This game uses submix voices to control volume:

log.txt:155401:24630.676:003e:trace:xaudio2:XA2SUB_SetVolume 0x60a0bd28,
0.000016, 0x0

Wine doesn't really implement submix processing yet, and it's not clear to me
what the best way is. Applying OpenAL effects to attached source voices? Making
a new OpenAL context for each voice and passing the software rendered audio
through each voice in the processing chain? Some combination depending on what
effects are applied?